Paper 2010/553

Strongly Secure Certificate-Based Encryption Scheme with Low Communication Bandwidth

Yang Lu

Abstract

Certificate-based encryption (CBE) is a new asymmetric encryption paradigm which was introduced to solve the certificate management problem in traditional public-key encryption (PKE). It combines PKE and identity-based encryption (IBE) while preserving some of their most attractive features. CBE provides an efficient implicit certificate mechanism which eliminates the third-party queries and simplifies the certificate revocation problem in the traditional PKI. It also solves the key escrow problem and the key distribution problem inherent in IBE. In this paper, we first present a new security model for CBE, which defines the public key replacement attack and strengthens the power of adversaries against CBE. Our model is more elaborated and stronger compared with other existing ones. We then propose an efficient CBE scheme which is proved to be secure in the proposed security model under the random oracle model. When compared with other existing CBE schemes, our scheme enjoys better performance, especially on the communication bandwidth.